Gravity flow or gravity induced livestock feeders have been used on farms and ranches for many years. Such feeders typically include a base member that serves as a feed trough, a hopper for storing and dispensing feed to the trough, and an animal actuated element or elements that agitate the feed when moved by a feeding animal. Some of these feeders also include a baffle within the hopper to control the flow of the feed. Animal actuated elements may facilitate the movement of feed to a location accessible to the feeding animal or prevent the bridging or caking of feed in or around the hopper or both. U.S. Pat. Nos. 2,644,425 and 4,353,329 are examples of feeders that incorporate a base feeding trough, hopper, and animal actuated elements.
U.S. Pat. No. 4,462,338 discloses a livestock feeder including a trough, hopper, feed wheel and deflector. The feed wheel is rotatable by feeding animals and includes an upright member extending through the hopper bottom aperture and a feed sweep connected to the upright member that facilitates the downward flow of feed. The generally conical deflector is positioned within the hopper above hopper bottom aperture. The deflector serves to (1) create an angle greater than the feed angle of repose created by the hopper side wall thereby minimizing adhesion of feed to the hopper side wall; (2) support most of the weight of the feed in the hopper that would otherwise be directed to the hopper bottom aperture; and (3) provide a mechanism for adjusting the feed flow rate.
U.S. Pat. No. 4,601,414 discloses a flow enhancement device for suspension in storage bins. The device includes an upper frusto conical portion and a lower cylindrical portion having a plurality of fins extending outwardly from the cylindrical portion. The device is suspended within a storage bin by three lines attached to the upper portion of the storage bin. In use, the flow enhancement device directs material flow and occasionally agitates material to provide uniform material flow.
U.S. Pat. No. 5,044,318 discloses a hog feeder having a base with an elevated central plateau which is turned down at a predetermined point into a circumferential inner wall and then outwardly into a circumferential bottom or trough. Individual feeding vanes are positioned on the plateau and are actuated by hogs feeding from the trough. Movement of a vane works the feed across the plateau radially causing feed to fall from the plateau edge down onto the trough.
In known livestock feeders the base member or trough often includes a stepped or inclined bottom. U.S. Pat. No. 4,401,057 discloses a hog feeding system having an immobile pan with a stepped bottom defining two distinct feeding areas (wet and dry). U.S. Pat. No. 2,512,260 discloses a stock feeding apparatus having agitating elements resting on a feed trough having an integral upwardly tapered conical feed distributor in the center of the feed trough.
While the above-cited patents show improvements and advances in gravity induced livestock feeders, there are some inadequately addressed problems. First, the quantity of feed available to the animals is difficult to control resulting in either wasted feed or a lack of feed which reduces weight gain by the animals.
Another problem associated with known gravity induced livestock feeders is that they include feed openings that may be restricted to reduce wastage. When the feed openings are restricted the feed will frequently stop flowing because: (1) the weight of the feed in the hopper packs the feed causing it to bridge; (2) moisture from the animals feeding or from rain soaks into the feed causing the feed to cake; (3) changes in humidity causes the feed flow characteristics to change; and (4) changes in feed formulation changes flow characteristics.
Still another problem with some known gravity induced livestock feeders is that they require mechanical adjustments to control the flow of feed.
Yet another problem is that, while agitators actuated by the animals to reduce feed from plugging may solve feed stoppage problems, these agitators also may encourage excess feeding.
Another problem is that it is common for animals to waste feed by spilling it out of the feed area or by getting dirt or manure in the feed area.
Still another problem is that aggressive animals are able to interfere with other feeding animals.
Additional concerns involve livestock feeders that use a wheel type structure that the animals rotate or oscillate with their noses when feeding. Feeders using wheel type structure are complicated and expensive.
Clearly, there is a need for an efficient, durable, economical gravity flow livestock feeder that provides the proper quantity of feed, minimizes blockage problems and protects the feed from contamination.